A .pst file is an export of your email account from outlook. This can include your email, contacts and calendars so is useful for either a backup or migrating from one account to another or even another computer.
Outlook New:
1. Select File > Open and export:
2. Now choose whether you wish to export a data file to save as a backup, or import one into your existing mailbox:
Export - now select the email account you wish to take a backup of, ticking Include subfolders if you wish to backup everything.
Import - now select Outlook Data File (.pst) > Get started.
On the next screen, click Select File, you will then have to locate the .pst file you have saved on your machine, and import it.
Older versions of Outlook
How to Export
1. Open Microsoft Outlook,
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3. Select Export to a File and Press Next.
4. Select Outlook Data File (.pst), Press Next
5. The window will now list your accounts and Folders [Click on your email account to export everything].
6. Tick include subfolders, Press Next
7. Save exported file as, browse where you want it to be saved (e.g to save to Desktop)
8. Then press OK
9. You will notice a .pst file created on your Desktop
How to Import
1. Open Microsoft Outlook,
2. Click on File > Open & Export > Import/Export
3. Select Import from another program or file, Press Next
4. Select Outlook Data File (.pst) Press Next
5. Browse the .pst file you created
6. Click on Next
